Improvement in Japanese Clinical Laboratory Measurements of Total Cholesterol and HDL-cholesterol by the US Cholesterol Reference Method Laboratory Network

Long-chain n-3 polyunsaturated fatty acids intake and cardiovascular disease mortality risk in Japanese: a 24-year follow-up of NIPPON DATA80

BACKGROUND

Dietary intake of long-chain n-3 PUFA (LCn3FA) among Japanese is generally higher than that in Western populations. However, little is known whether an inverse association of LCn3FA with cardiovascular disease (CVD) risk exists in a population with higher LCn3FA intake.

OBJECTIVE

To investigate the association between LCn3FA intake and the long-term risk of CVDs in a Japanese general population.

METHODS

We followed-up a total of 9190 individuals (56.2% women, mean age 50.0 years) randomly selected from 300 areas across Japan and free from CVDs at baseline. Dietary LCn3FA intake was estimated using household weighed food records. Cox models were used to calculate multivariate-adjusted hazard ratios (HR) and confidence intervals (CI) according to sex specific quartiles of LCn3FA intake.

RESULTS

During 24-year follow-up (192,897 person-years), 879 cardiovascular deaths were observed. The median daily intake of LCn3FA was 0.37% kcal (0.86 g/day). Adjusted HR for CVD mortality was lower in the highest quartile of LCn3FA intake (HR 0.80; 95% CI 0.66-0.96) compared with the lowest quartile, and the trend was statistically significant (P = 0.038). The similar but statistically non-significant trends were observed for coronary heart disease death and stroke death. In analyses by age groups, the inverse associations of LCn3FA intake with the risk of total CVD death and stroke death were significant in younger individuals (30-59 years at baseline).

CONCLUSION

LCn3FA intake was inversely and independently associated the long-term risk of total CVD mortality in a representative sample of Japanese with high LCn3FA intake.

An association between central aortic pressure and subclinical organ damage of the heart among a general Japanese cohort: Circulatory Risk in Communities Study (CIRCS)

BACKGROUND

This study aimed to investigate associations between central aortic pressure (CAP) and subclinical organ damage of the heart amongst the general population.

METHODS

We conducted a cross-sectional study in a community-based population, consisting of 3002 men and women aged between 40 and 79 years. The CAP was measured using the HEM-9000AI device, an automated tonometer. Electrocardiograms (ECG) were read according to the Minnesota Code. Subclinical organ damage in the heart was defined as measurable left high amplitude R waves (LHAR), major and minor ST-T abnormalities, and left ventricular hypertrophy (LVH).

RESULTS

Age- and sex-adjusted prevalence of LHAR, major and minor ST-T abnormalities, and LVH was higher for subjects in the highest tertile of CAP levels than those in the lowest tertile. After further adjustments for other cardiovascular risk factors, these associations did not change substantially. The multivariable odds ratios (ORs) (95% CI) of LHAR, major and minor ST-T abnormalities, and LVH for the highest tertile of CAP levels compared to the lowest tertile were 2.7(1.9-3.9), 1.8(1.1-2.9), 1.7(1.3-2.3) and 3.2(1.3-8.1), respectively. The positive associations with LHAR and minor ST-T abnormalities were observed primarily among non-hypertensive subjects. The respective corresponding ORs were 2.8(1.7-4.6) and 1.7(1.2-2.4) for non-hypertensive subjects, and 1.7(0.9-3.3) and 1.1(0.7-1.8) for hypertensive subjects.

CONCLUSION

CAP levels were associated with subclinical organ damage of the heart independent of cardiovascular risk factors, and these associations were primarily seen in non-hypertensive subjects.

HbA1c and the risks for all-cause and cardiovascular mortality in the general Japanese population: NIPPON DATA90

OBJECTIVE

Associations between HbA1c and cardiovascular diseases (CVD) have been reported mainly in Western countries. It is not clear whether HbA1c measurements are useful for assessing CVD mortality risk in East Asian populations.

RESEARCH DESIGN AND METHODS

The risk for cardiovascular death was evaluated in a large cohort of participants selected randomly from the overall Japanese population. A total of 7,120 participants (2,962 men and 4,158 women; mean age 52.3 years) free of previous CVD were followed for 15 years. Adjusted hazard ratios (HRs) and 95% CIs among categories of HbA1c (<5.0%, 5.0-5.4%, 5.5-5.9%, 6.0-6.4%, and ≥6.5%) for participants without treatment for diabetes and HRs for participants with diabetes were calculated using a Cox proportional hazards model.

RESULTS

During the study, there were 1,104 deaths, including 304 from CVD, 61 from coronary heart disease, and 127 from stroke (78 from cerebral infarction, 25 from cerebral hemorrhage, and 24 from unclassified stroke). Relations to HbA1c with all-cause mortality and CVD death were graded and continuous, and multivariate-adjusted HRs for CVD death in participants with HbA1c 6.0-6.4% and ≥6.5% were 2.18 (95% CI 1.22-3.87) and 2.75 (1.43-5.28), respectively, compared with participants with HbA1c <5.0%. Similar associations were observed between HbA1c and death from coronary heart disease and death from cerebral infarction.

CONCLUSIONS

High HbA1c levels were associated with increased risk for all-cause mortality and death from CVD, coronary heart disease, and cerebral infarction in general East Asian populations, as in Western populations.

Predictive value of lipoprotein indices for residual risk of acute myocardial infarction and sudden death in men with low-density lipoprotein cholesterol levels <120 mg/dl

Several epidemiologic studies have demonstrated that plasma low-density lipoprotein cholesterol (LDL-C) profile is a key risk indicator for coronary heart disease (CHD). However, almost half of all patients with CHD have normal LDL-C levels. A total of 7,931 male subjects aged ≥40 years from the general population with no cardiovascular history and no use of lipid-lowering agents were followed for incidence of acute myocardial infarction (AMI) and sudden death. Of the 4,827 participants with LDL-C levels <120 mg/dl, 55 subjects had a first AMI/sudden death during an average of 5.5 years of follow-up. After adjustment for confounding factors, multiadjusted hazard ratios (HRs) were increased by 1 SD for non-high-density lipoprotein cholesterol (non-HDL-C; HR = 1.36, 95% confidence interval [CI], 1.02 to 1.81), total cholesterol (TC)/HDL-C ratio (HR = 1.40, 95% CI: 1.11 to 1.78) and LDL-C/HDL-C ratio (HR = 1.32, 95% CI: 1.02 to 1.73) but not for LDL-C (HR = 1.09, 95% CI: 0.82 to 1.44) and HDL-C (HR = 0.84, 95% CI: 0.68 to 1.04). When stratified as categorical variables on the basis of points with highest accuracy on receiver operating characteristic analysis, non-HDL-C levels >126 mg/dl (HR = 1.25, 95% CI: 1.03 to 1.51), TC/HDL-C ratio above 3.5 (HR = 1.22, 95% CI: 1.01 to 1.48) and LDL-C/HDL-C ratio >1.9 (HR = 1.25, 95% CI: 1.04 to 1.51) had increased multiadjusted HRs for AMI/sudden death. In conclusion, in men with LDL-C levels <120 mg/dl, non HDL-C, TC/HDL-C, and LDL-C/HDL-C ratios have predictive value for residual risk of AMI/sudden death.

Association of alcohol consumption with incident hypertension among middle-aged and older Japanese population: the Ibarakai Prefectural Health Study (IPHS)

The objective of this study was to examine the effect of age on the relationship between alcohol consumption and incident hypertension in a general Japanese population. A cohort of Japanese men (n=37 310) and women (n=78 426) aged 40 to 79 years who underwent community-based health checkups from 1993 to 2004 and were free of hypertension were followed up with annual examinations, including the measurement of blood pressure, until the end of 2010. Incident hypertension was defined as systolic blood pressure of ≥140 mm Hg, diastolic blood pressure of ≥90 mm Hg, or the initiation of treatment for hypertension. Hazard ratios for incident hypertension according to alcohol consumption were estimated using a Cox proportional hazards model adjusted for possible confounding variables. A total of 45 428 participants (39.3%) developed hypertension (16 155 men and 29 273 women) for a mean follow-up time of 3.9 (1-18) years. Significant associations between alcohol consumption and incident hypertension were found in both sexes and age groups (P for trend was <0.001 for men aged 40-59 years and aged 60-79 years; 0.004 for women aged 40-59 years and 0.026 for women aged 60-79 years). No significant interaction with age on the association of alcohol consumption with incident hypertension was found in either sex (P for interaction, >0.05). Our results suggest that alcohol consumption is a similar risk factor for incident hypertension in both the middle-aged and the older populations.

Low serum LDL cholesterol levels are associated with elevated mortality from liver cancer in Japan: the Ibaraki Prefectural health study

Liver cancer a global public health concern and well known for poor prognosis. The association between low total cholesterol level and liver cancer has been reported. However, the association between low low-density lipoprotein (LDL) cholesterol levels and liver cancer is still unclear. The aim of this study was to examine the relationship between LDL cholesterol level and liver cancer mortality. A total of 16,217 persons (5,551 men and 10,666 women) aged 40-79 years in 1993 were followed until 2008. LDL cholesterol levels were divided into four categories (<80 mg/dl, 80-99 mg/dl, 100-119 mg/dl, and ≥120 mg/dl). Hazard ratio of LDL cholesterol level for liver cancer mortality was calculated using a multivariable Cox proportional hazards model. Covariates were age, sex, alanine transaminase, body mass index, alcohol intake and smoking status, all of which were correlated with LDL cholesterol levels. There were 51 deaths (32 men and 19 women) from liver cancer. Multivariable hazard ratios of liver cancer deaths for LDL cholesterol levels of <80 mg/dl was 4.33 (95% confident interval [CI]: 1.94, 9.68), for LDL cholesterol levels of 80-99 mg/dl was 1.03 (95% CI: 0.42, 2.53), and for LDL cholesterol levels of ≥120 mg/dl was 0.43 (95% CI: 0.20, 0.92) compared with LDL cholesterol levels of 100-199 mg/dl (p for trend<0.01). Therefore, low LDL cholesterol levels are associated with elevated risk of liver cancer mortality. Low LDL cholesterol may be a predictive marker for death due to liver cancer.

Carotid intima-media thickness and plaque in apparently healthy Japanese individuals with an estimated 10-year absolute risk of CAD death according to the Japan Atherosclerosis Society (JAS) guidelines 2012: the Shiga Epidemiological Study of Subclinical Atherosclerosis (SESSA)

AIM

To examine whether subclinical atherosclerosis of the carotid arteries is concordant with the categories in the 2012 atherosclerosis prevention guidelines proposed by the Japan Atherosclerosis Society (JAS guidelines 2012), which adopted the estimated 10-year absolute risk of coronary artery disease (CAD) death in the NIPPON DATA80 Risk Assessment Chart.

METHODS

Between 2006 and 2008, 868 Japanese men 40 to 74 years of age without a history of cardiovascular disease were randomly selected from Kusatsu City, Japan. The intima media thickness (IMT) and plaque number from the common to internal carotid arteries were investigated using ultrasonography. The absolute risk of CAD death was estimated based on the individual risk factor data, and the mean IMT and plaque number in Categories Ⅰ, Ⅱ and Ⅲ of the guidelines were examined.

RESULTS

The estimated 10-year absolute risk of CAD was directly related to the IMT (mean IMT (mean ± SD) (mm) for a 10-year absolute risk of ≥ 2.0% and ≥ 5.0%: 0.88 ± 0.18 and 0.95 ± 0.19, respectively) and the plaque number. These results are compatible with the categories described by the guidelines (mean IMT (mean ± SD) (mm) for Categories Ⅰ, Ⅱ, and Ⅲ: 0.70 ± 0.11, 0.81 ± 0.16 and 0.88 ± 0.18, respectively; mean plaque number: 0.9, 2.1 and 3, respectively). These findings were similar for Category Ⅲ participants with or without DM and CKD.

CONCLUSIONS

Subclinical atherosclerosis of the carotid arteries is concordant with the 10-year absolute risk of CAD and the categories in the JAS guidelines 2012.

Factors related to tooth loss among community-dwelling middle-aged and elderly Japanese men

Background

Using data from a large-scale community-based Japanese population, we attempted to identify factors associated with tooth loss in middle-aged and elderly men.

Methods

A total of 8352 men aged 40 to 79 years who lived in the north of the main island of Japan and underwent health checkups were enrolled between 2002 and 2005. Number of teeth was assessed by the question, “How many teeth do you have (0, 1–9, 10–19, or ≥20)?”. On the basis of the answer to this question, participants were classified into 2 groups (≤19 teeth or ≥20 teeth). Using multivariate logistic regression, factors related to having 19 or fewer teeth were estimated.

Results

The numbers (percentages) of participants who had 0, 1 to 9, 10 to 19, and 20 or more teeth were 1764 (21.1%), 1779 (21.3%), 1836 (22.0%), and 2973 (35.6%), respectively. Among the participants overall and those aged 65 to 79 years, having 19 or fewer teeth was significantly associated with older age, smoking status (current smoking and ex-smoking), and low education level. In addition, men with 19 or fewer teeth were more likely to have a low body mass index and low serum albumin level and less likely to be current alcohol drinkers. Among men aged 40 to 64 years, but not men aged 65 to 79 years, those with 19 or fewer teeth were more likely to have a low serum high-density lipoprotein cholesterol level and high glycosylated hemoglobin (HbA1c) level.

Conclusions

Smoking, low education level, and poor nutritional status were associated with tooth loss among middle-aged and elderly Japanese men.

Total and high molecular weight adiponectin levels and risk of cardiovascular disease in individuals with high blood glucose levels

OBJECTIVE

The association of adiponectin levels with cardiovascular disease (CVD) may vary by age and health condition. It is unknown whether adiponectin predicts CVD events among individuals with high blood glucose levels.

METHODS

We conducted a nested case-control study among 15,566 men and women aged 40-85 years from four communities, who were free of CVD at baseline. During 192,181 person-years of follow-up, 117 individuals subsequently developed coronary heart disease or ischemic stroke and had high plasma glucose concentrations (fasting/nonfasting ≥ 5.6/7.2 mmol/L or treated) at baseline. Controls were randomly selected at a 2:1 ratio and matched for sex, age, blood glucose, year of survey, fasting conditions, and community (n = 234). Baseline total and high molecular weight (HMW) adiponectin and their ratio were examined for total subjects and the association with CVD was compared between ages of 40-69 and 70-85 years.

RESULTS

After adjustment for matched variables and traditional risk factors, total and HMW adiponectin and their ratio were not associated with overall risk of CVD. However, significant interactions of the associations between the age groups were found. The highest quartile for HMW adiponectin and HMW/total adiponectin ratio decreased risk of CVD compared with the lowest quartile among middle-aged individuals (multivariable-adjusted odds ratio = 0.33 [95%CI, 0.13-0.83] and 0.47 [0.22-0.98], respectively), while this association was not seen among the elderly.

CONCLUSIONS

High HMW adiponectin levels may decrease the risk of CVD in middle-aged adults with high blood glucose.

Non-fasting blood glucose and risk of incident coronary heart disease in middle-aged general population: the Circulatory Risk in Communities Study (CIRCS)

OBJECTIVE

The objective was to determine whether non-fasting glucose concentration is a predictor for incident coronary heart disease.

METHODS

We investigated a cohort data of 9,900 40- to 69-year-old residents in four Japanese communities for 1975-1986 baseline surveys of the Circulatory Risk in Communities Study (CIRCS). Non-fasting blood glucose concentrations were available for 7,332 participants. Diabetic type was defined as a glucose level of ≥ 11.1 mmol/L and/or the use of medication for diabetes mellitus.

RESULTS

A total of 170 coronary heart disease including 113 myocardial infarctions occurred in non-fasting participants within the median 22-year follow-up period. Multivariable hazard ratios (HRs) of incident coronary heart disease for the participants with diabetic type compared with the normal type were 1.98 (0.84-4.68) for men, 3.39 (1.47-7.81) for women, and 2.47 (1.37-4.46) for total subjects. Corresponding HRs for myocardial infarction were 2.14 (0.83-5.55), 5.70 (2.21-14.67) and 3.17 (1.65-6.10), respectively. Multivariable HRs of incident coronary heart disease per one standard deviation of serum glucose levels were 1.17 (1.02-1.36), 1.19 (1.03-1.38), and 1.19 (1.08-1.32), respectively. The corresponding HRs for myocardial infarction were 1.18 (1.00-1.38), 1.27 (1.07-1.49) and 1.23 (1.10-1.37).

CONCLUSION

Non-fasting glucose concentration, either as diagnosis of diabetic type or as continuous variable, proved to be an independent predictor for incident coronary heart disease in middle-aged general population.

Methodological issues for a large-scale intervention trial of lifestyle modification: Interim assessment of the high-risk and population strategy for occupational health promotion (HIPOP-OHP) study

OBJECTIVE

To clarify the methodological issues for the High-risk and population Strategy for Occupational Health Promotion Study (HIPOP-OHP study), which is a 4-year non-randomized control trial, an interim assessment of male participants was performed 3 years after the baseline survey.

METHODS

We had approximately 2,500 and 4,000 participants in the intervention and control groups, respectively. The population measures and prevalence of risk factors at each year, and between the baseline and 4th examinations were compared between the two groups. The personal trends of returning participants who were in the study at the 1(st) and 4(th) examinations were also evaluated.

RESULTS

During the 3 years, an increase in serum HDL cholesterol (2.7 mg/dl), and a reduction in the prevalence of hypertriglycemia detected with fasting blood samples (3.6%) and current smokers (5.4%) were observed in the intervention group. The mean HDL cholesterol level was significantly higher in the intervention group than in the control group at the 4th examination, reversed from the baseline survey. The serum non-HDL cholesterol level was significantly increased only in the control group. There was also a significant increase in the prevalence of hypertriglycemia nad high plasma glucose detected with fasting blood samples in the control group. The return participation rate after 3 years was 72.2% for the intervention group and 74.9% for the control group. The above-mentioned changes for risk factors were mainly due to returning participants at each examination.

CONCLUSION

These interventional methods may be effective in improving overall cardiovascular risk factors in the population. However, the low return participation rate will dilute the effect of the intervention.

Risk factors for sudden cardiac death among Japanese: the Circulatory Risk in Communities Study

OBJECTIVE

There is little evidence concerning risk factors for sudden cardiac death (SCD) among Asians.

PATIENTS AND METHODS

A prospective, nested, case-control study of Japanese patients aged between 30 and 84 years was undertaken using data collected from 26 870 participants in cardiovascular risk surveys conducted in four communities between 1975 and 2005. The incidence of SCD was ascertained by systematic surveillance, with 239 cases of SCD identified over this period. For each case of SCD, three control patients were selected, matched by age, sex, examination year, follow-up time, and community.

RESULTS

Hypertension, diabetes mellitus, smoking, major ST-T abnormalities, left high amplitude R waves, and increased heart rate (≥77 beat/min) were all independently associated with a 1.5-3.2-fold increase in SCD risk, whereas no associations were observed for body mass index and hypercholesterolemia. The population-attributable fraction [95% confidence interval (CI)] was 23.0% (2.9-39.0) for hypertension, 15.3% (3.8-25.5) for current smoking, 14.5% (8.0-20.5) for major ST-T abnormalities, and 8.1% (2.2-13.7) for diabetes mellitus. The number of SCD risk factors (hypertension, diabetes, smoking, and ECG abnormalities) was positively associated with increased SCD risk. The odds ratio for increased SCD risk with three or more risk factors versus zero risk factors was 5.76 (95% CI 3.20-10.39).

CONCLUSIONS

Among the Japanese population, hypertension, smoking, major ST-T abnormalities, left high amplitude R waves, and diabetes mellitus were associated with an increased incidence of SCD, whereas there were no associations of body mass index or hypercholesterolemia with SCD incidence.

Impact of obesity on incident hypertension independent of weight gain among nonhypertensive Japanese: the Ibaraki Prefectural Health Study (IPHS)

OBJECTIVE

The aim of this study was to examine the association between BMI and risk of incident hypertension among Japanese men and women who are middle-aged and older.

DESIGN

Prospective, population-based cohort study.

PATIENTS

A total of 68 205 nonhypertensive adults (18 336 men and 49 869 women) aged 40-79 years who completed health check-ups in the Ibaraki prefecture, Japan, in 1993 were followed up through 2006. To exclude the impact of BMI change during the follow-up period, a time-dependent covariate Cox proportional hazards model was used to compute the hazard ratios of incident hypertension according to BMI categories. Incident hypertension was defined as a SBP of at least 140 mmHg, a diastolic BP of at least 90 mmHg, and/or hypertensive medication use.

RESULTS

A total of 30 982 adults (45.4%) developed hypertension (9331 men and 21 651 women) during a mean of 3.9 years of follow-up. Compared with a BMI of less than 19.0, time-dependent covariates adjusted hazard ratios [95% confidence interval (CI)] for hypertension among participants with a BMI of at least 25.0 were 1.42 (1.17-1.73) for men aged 40-59 years, 1.34 (1.19-1.51) for men aged 60-79 years, 1.47 (1.33-1.62) for women aged 40-59 years, and 1.29 (1.18-1.41) for women aged 60-79 years.

CONCLUSION

The baseline BMI is associated with future risk for incident hypertension even after accounting for weight change during the follow-up period. Weight loss may be recommended to nonhypertensive obese adults to prevent the development of hypertension.

Alkaline phosphatase and risk of stroke among Japanese: the Circulatory Risk in Communities Study (CIRCS)

Although serum alkaline phosphatase (ALP) levels have been associated with mortality from all-cause and from either ischemic or hemorrhagic stroke, no study has been published of the associations between ALP and the incidence of stroke. We therefore examined the associations of ALP with risk of stroke among Japanese, stratified by drinking status because ALP is known as an enzyme affected by alcohol consumption. We conducted a prospective cohort study of 10,754 Japanese subjects (4098 men and 6656 women) aged 40-69 years and living in 4 communities under systematic surveillance for stroke incidence. During the 16-year follow-up, we documented 264 strokes (164 ischemic strokes and 69 hemorrhagic strokes) for men and 225 strokes (118 ischemic strokes and 89 hemorrhagic strokes) for women. There was a U-shaped association between ALP level and stroke incidence in both men and women, which was confined primarily to nondrinkers. For nondrinkers, higher ALP levels were associated with an elevated risk of ischemic stroke for men and of hemorrhagic stroke for women, whereas lower ALP levels were associated with elevated risks of ischemic and hemorrhagic strokes in both men and women. Our data indicate that not only higher, but also lower, serum ALP level may be a predictor for the risk of stroke in nondrinking men and women.

Cellular growth factors in relation to mortality from cardiovascular disease in middle-aged Japanese: the JACC study

OBJECTIVE

Limited evidence has been available on the relationships of cellular growth factors with cardiovascular disease in population-based samples.

METHODS

We conducted a nested case-control study under a large prospective cohort study (JACC study) where a total of 39,242 subjects aged 40-79 years provided serum sample. We measured cellular growth factors [insulin-like growth factors I, II and binding protein-3 (IGF-I, IGF-II and IGFBP-3) and transforming growth factor (TGF-β1)] among cases and controls, matched for sex, age, area of residence and year of serum storage.

RESULTS AND CONCLUSIONS

During the follow-up for 9 years, there were 233 deaths from total stroke (49 subarachnoid hemorrhages, 55 intraparenchymal hemorrhages, 71 ischemic strokes), and 97 deaths from coronary heart disease. The multivariable odds ratio (95%CI) of intraparenchymal hemorrhage associated with a 1-SD increment of IGF-I (men:4 8 ng/ml, women: 61 ng/ml) was 0.31 (0.14-0.71). That of ischemic stroke associated with a 1-SD increment of TGF-β1 (men: 8.0 ng/ml, women: 10.9 ng/ml) was 0.58 (0.34-0.98). Serum IGF-II and IGFBP-3 were not associated with mortality from any outcomes. In conclusion, IGF-I was inversely associated with mortality from intraparenchymal hemorrhage while TGF-β1 was so with ischemic stroke, suggesting potential roles of cellular proliferation in the development or prognosis of stroke.

Relation of serum α- and γ-tocopherol levels to cardiovascular disease-related mortality among Japanese men and women

Background

There is limited evidence regarding the relationship between serum tocopherol levels and cardiovascular disease.

Methods

We conducted a nested case-control study as part of the Japan Collaborative Cohort Study for evaluation of cancer risk (JACC Study). Baseline serum samples were collected from 39 242 participants (age range, 40–79 years) between 1988 and 1990. During the 13-year follow-up, there were 530 stroke deaths (302 ischemic strokes and 210 hemorrhagic strokes) and 211 deaths from coronary heart disease. Controls were matched for sex, age, and area of residence.

Results

Serum α-tocopherol level was not associated with any type of cardiovascular death in men; however, in women, it was inversely associated with total stroke mortality and hemorrhagic stroke mortality. The multivariate odds ratio (95% CI) for the highest versus the lowest quintile of serum α-tocopherol levels among women was 0.35 (0.16–0.77; P for trend = 0.009) for total stroke and 0.26 (0.07–0.97; P for trend = 0.048) for hemorrhagic stroke. Serum γ-tocopherol was inversely associated with ischemic stroke mortality in men but positively associated with hemorrhagic stroke mortality in women. The respective multivariate odds ratios (95% CI) for the highest versus the lowest quintile and for a 1-standard deviation increment in γ-tocopherol level were 0.48 (0.22–1.06; P for trend = 0.07) and 0.77 (0.58–1.02), respectively, for ischemic stroke in men and 3.10 (0.95–10.12; P for trend = 0.052) and 1.49 (1.04–2.13) for hemorrhagic stroke in women.

Conclusions

Among women, hemorrhagic stroke mortality was inversely associated with serum α-tocopherol and positively associated with serum γ-tocopherol. These findings are due in part to the antioxidative and antithrombotic activities of these tocopherols.

Prognostic Values of Clockwise and Counterclockwise Rotation for Cardiovascular Mortality in Japanese Subjects

Background—

Although clockwise rotation and counterclockwise rotation are distinct findings of the ECG, their prognostic significance is rarely studied.

Methods and Results—

We studied prognostic values of clockwise and counterclockwise rotation on total, cardiovascular disease (CVD), and subtype mortality using the National Integrated Project for Prospective Observation of Noncommunicable Disease and Its Trends in the Aged, 1980–2004 (NIPPON DATA80) database with a 24-year follow-up. At baseline in 1980, data were collected on study participants aged ≥30 years from randomly selected areas in Japan. We followed 9067 participants (44% men; mean age, 51 years). During the 24-year follow-up, mortality was as follows: 2581 total, 887 CVD, 179 coronary heart disease, 173 heart failure, and 411 stroke. The multivariate-adjusted hazard ratio (HR) with the use of the Cox model including biochemical and other ECG variables revealed that clockwise rotation was significantly positively associated with heart failure in men and women combined (HR=1.79; 95% confidence interval [CI], 1.13–2.83; P =0.013), CVD in men and in men and women combined (HR=1.49; 95% CI, 1.12–1.98; P =0.007 in men; HR=1.28; 95% CI, 1.02–1.59; P =0.030 in combined), and total mortality in men and in men and women combined (HR=1.19; 95% CI, 1.00–1.49; P =0.0496 in men; HR=1.15; 95% CI, 1.00–1.32; P =0.045 in combined). Counterclockwise rotation was significantly inversely associated stroke in men and women combined (HR=0.77; 95% CI, 0.62–0.96; P =0.017), CVD in men and in men and women combined (HR=0.74; 95% CI, 0.59–0.94; P =0.011 in men; HR=0.81; 95% CI, 0.70–0.94; P =0.006 in combined), and total mortality in women (HR=0.87; 95% CI, 0.77–0.98; P =0.023).

Conclusions—

We found a significant positive association of clockwise rotation and a significant inverse association of counterclockwise rotation with CVD mortality in men and in men and women combined, independent of confounding factors including other ECG changes.

High serum total cholesterol levels is a risk factor of ischemic stroke for general Japanese population: the JPHC study

BACKGROUND

High serum total cholesterol levels represent a risk factor of ischemic stroke in Western countries. However, this association has not been thoroughly investigated in Asian populations where the incidence of stroke is high.

METHODS

Participants were 11,727 men and 21,742 women aged 40-69 years, all free of cardiovascular disease and cancer at baseline. During the median 12-year follow-up, we documented 612 ischemic stroke (293 lacunar infarction, 107 large-artery occlusive infarctions, and 168 embolic infarctions).

RESULTS

Excess risk of ischemic stroke was observed in men with serum total cholesterol levels of ≥ 6.21 mmol/L than those with the lowest category (<4.65 mmol/L), but not in women. The multivariable hazard ratios (HRs) and 95% confidence interval (95% CI) were 1.63 (1.14-2.35) for men and 1.03 (0.69-1.55) for women. The corresponding HRs of large-artery occlusive infarction were 2.86 (1.31-6.27) for men and 0.75 (0.28-2.01) for women. Serum total cholesterol levels were not associated with risk of lacunar or embolic infarction for either sex.

CONCLUSIONS

High serum total cholesterol is a risk factor of ischemic stroke, specifically large-artery occlusive infarction for Japanese men.

Relationship between Dietary and Other Lifestyle Habits and Cardiometabolic Risk Factors in Men

BACKGROUND

Prevalence of men with cardiometabolic risk factors (CMRF) is increasing in Japan. Few studies have comprehensively examined the relation between lifestyles and CMRF.

METHODS

We examined the baseline data from 3,498 male workers ages 19 to 69 years who participated in the high-risk and population strategy for occupational health promotion (HIPOP-OHP) study at 12 large-scale companies throughout Japan. The physical activity of each participant was classified according to the International Physical Activity Questionnaire (IPAQ). Dietary intake was surveyed by a semi-quantitative Food Frequency Questionnaire. We defined four CMRF in this study as follows: 1) high blood pressure (BP): systolic BP ≥ 130 mmHg, or diastolic BP ≥ 85 mmHg, or the use of antihypertensive drugs; 2) dyslipidemia: high-density lipoprotein-cholesterol concentration < 40 mg/dl, or triglycerides concentration ≥ 150 mg/dl, or on medication for dyslipidemia; 3) impaired glucose tolerance: fasting blood sugar concentration ≥110 mg/dl; 4) obese: a body mass index ≥ 25 kg/m2.

RESULTS

Those who had 0 to 4 CMRF accounted for 1,597 (45.7%), 1,032 (29.5%), 587 (16.8%), 236 (6.7%), and 44 (1.3%) participants, respectively, in the Poisson distribution. Poisson regression analysis revealed that independent factors that contributed to the number of CMRF were age (b = 0.020, P < 0.01), IPAQ (b = -0.091, P < 0.01), alcohol intake (ml/day) (b = 0.001, P = 0.03), percentage of protein intake (b = 0.059, P = 0.01), and total energy intake (kcal)(b = 0.0001, P < 0.01). Furthermore, alcohol intake and its frequency had differential effects.

CONCLUSIONS

Alcohol intake, percent protein and total energy intake were positively associated, whereas drinking frequency and IPAQ were inversely associated, with the number of CMRF.

Exposure to particulate matter and long-term risk of cardiovascular mortality in Japan: NIPPON DATA80

AIM

It remains uncertain whether chronic exposure to particulate air pollution is associated with increased mortality in Japan because Japan has a different distribution pattern of cardiovascular disease and its risk factors compared to Western countries. We investigated the association between long-term exposure to particulate matter (PM) and cardiovascular mortality risk using a representative Japanese cohort.

METHODS

A total of 7,250 participants aged 30 years and older from 232 districts throughout Japan were followed from 1980 to 2004. We linked the averaged annual concentrations of PM from 1985 to 2004 to each cohort participant who resided in the district at the time of the baseline survey. Study participants were divided into quintiles of average PM concentration. We applied the Cox proportional hazard model adjusting for sex, age, body mass index, blood pressure, total cholesterol, blood glucose, smoking categories, drinking categories, and the municipality population size.

RESULTS

During follow-up, there were 1,716 deaths from all causes; 571 from cardiovascular disease, 116 from coronary heart disease, and 250 from stroke. Hazard ratios were not different among the quintiles and those for trend per 10 µg/m3 increase in annual PM concentration were 0.98 (95% confidence interval, 0.92-1.04) for all-cause mortality and 0.90 (95% confidence interval, 0.81-1.00) for cardiovascular mortality.

CONCLUSION

Long-term exposure to PM was not associated with increased cardiovascular mortality risk in this population-based cohort in Japan.

Relationship between health-related quality of life and clustering of metabolic syndrome diagnostic components

PURPOSE

To examine the association of the number of metabolic syndrome diagnostic components (MetS-DC) with health-related quality of life (HR-QOL).

METHODS

We examined the baseline data from 4,480 healthy workers in Japan (3,668 men and 812 women) aged 19-69 years. We assessed HR-QOL based on scores for five scales of the SF-36. We defined four components for MetS in this study as follows: (1) high blood pressure (BP); (2) dyslipidemia; (3) impaired glucose tolerance; and (4) overweight: a body mass index ≥25 kg/m(2). Logistic regression analysis adjusted for lifestyle factors was used to examine the association of the number of MetS-DC with the HR-QOL sub-scales.

RESULTS

Those who had 0-4 MetS-DC accounted for 2,287, 1,135, 722, 282, and 54 participants. The number of MetS-DC inversely contributed significantly to General Health (norm-based scoring >50) (odd ratios [OR] 0.59-0.82, P < 0.05) and positively associated with Mental Health (OR 1.37, P < 0.05).

CONCLUSION

When adjusted for lifestyle factors, the number of MetS-DC was inversely associated with General Health and positively with Mental Health in men and women.

Prognostic value of ST-T abnormalities and left high R waves with cardiovascular mortality in Japanese (24-year follow-up of NIPPON DATA80)

Little is known about the prognostic value of ST-segment depression and/or T wave (ST-T abnormalities) with or without left high R waves on electrocardiogram recorded at rest for death from cardiovascular disease (CVD) in Asian populations. Japanese participants without a history of CVD and free of major electrocardiographic (ECG) abnormalities were followed for 24 years. Subjects were divided into 4 groups based on baseline ECG findings: isolated left high R waves, isolated ST-T abnormalities, ST-T abnormalities with left high R waves, and normal electrocardiogram. Cox proportional hazard model was used to estimate risk of CVD mortality in groups with ECG abnormalities compared to the normal group. Of 8,572 participants (44.4% men, mean age 49.5 years; 55.6% women, mean age 49.4 years), 1,142 had isolated left high R waves, 292 had isolated ST-T abnormalities, and 128 had ST-T abnormalities with left high R waves at baseline. Multivariable-adjusted hazard ratios of ST-T abnormalities with left high R waves for CVD mortality were 1.95 (95% confidence interval 1.25 to 3.04) in men and 2.68 (95% confidence interval 1.81 to 3.97) in women. Isolated ST-T abnormalities increased the risk for CVD death by 1.66 times (95% confidence interval 1.01 to 2.71) in men and 1.62 times (95% confidence interval 1.18 to 2.24) in women. Association of ECG abnormalities with CVD mortality was independent of age, body mass index, systolic blood pressure, serum cholesterol, blood glucose, smoking and drinking, and antihypertensive medication. In conclusion, ST-T abnormalities with or without left high R waves on electrocardiogram recorded at rest constitute an independent predictor of CVD mortality in Japanese men and women.

Pulse pressure is an independent risk factor for stroke among middle-aged Japanese with normal systolic blood pressure: the JPHC study

OBJECTIVE

Although pulse pressure has been recognized a risk factor for coronary heart disease in both middle-aged and elderly, and for stroke in the elderly, the contribution of pulse pressure to the risk of stroke among the middle-aged is uncertain.

METHODS

A total of 33 372 participants (11 684 men and 21 688 women aged 40-69 years) living in communities, free of prior diagnosis of cardiovascular disease and cancer, completed health check-up examination. They were followed from 1990-1992 to the end of 2004 in the Japan public health center-based prospective study on cancer and cardiovascular disease. After 422 864 person-years of follow-up, 1081 incident strokes (559 men and 522 women) were documented.

RESULTS

Pulse pressure was positively associated with risk of stroke as was systolic and diastolic blood pressures. The multivariable hazard ratio of total stroke associated with a 1-SD increment (13.2 mmHg) of pulse pressure was 1.14 (1.05-1.24). The excess risk was observed for the stratum of systolic blood pressure below 140 mmHg, but not of higher systolic blood pressure levels after adjustment for diastolic blood pressure and other potential confounding factors; the multivariable hazard ratio of stroke associated with a 1-SD increment of pulse pressure was 1.32 (1.07-1.64) among persons with normal systolic blood pressure levels.

CONCLUSIONS

Pulse pressure is a risk factor for stroke among normotensive individuals with systolic blood pressure below 140 mmHg, which suggests that pulse pressure may be useful to predict the risk of stroke among middle-aged nonsystolic hypertensive patients.

Low-density lipoprotein cholesterol and risk of coronary heart disease among Japanese men and women: the Circulatory Risk in Communities Study (CIRCS)

OBJECTIVE

The objective of this study was to assess the association between serum LDL-cholesterol levels and risk of coronary heart disease (CHD) among Japanese who have lower means of LDL-cholesterol than Western populations.

METHODS

The predictive power of estimated serum LDL-cholesterol levels in casual blood samples for risk of CHD was evaluated among residents from four Japanese communities participating in the Circulatory Risk in Communities Study (CIRCS). A total of 8131 men and women, aged 40 to 69 years with no history of stroke or CHD, completed baseline risk factor surveys between 1975 and 1987. By 2003, 155 cases of incident CHD (myocardial infarction, angina pectoris and sudden cardiac death) had been identified.

RESULTS

Mean LDL-cholesterol values were 99.4 mg/dL for men and 109.4 mg/dL for women. The crude incidence rate (per 100,000 person-years) of CHD was 152.0 for men and 51.9 for women. The respective multivariable hazard ratios for ≥ 140 mg/dL versus <80mg/dL LDL-cholesterol were 2.80 (95% confidence interval: 1.59 to 4.92) for total CHD, 3.83 (1.78-8.23) for myocardial infarction, 4.07 (2.02-8.20) for non-fatal CHD, and 1.24 (0.44-3.47) for fatal CHD.

CONCLUSION

Serum LDL-cholesterol levels ranging from around 80 mg/dL to 200mg/dL were positively associated with risk of CHD in a Japanese population.

Relationship between sleep duration and clustering of metabolic syndrome diagnostic components

OBJECTIVE

To examine the relation between sleep duration and metabolic syndrome (MetS).

METHODS

We examined the baseline data from 4356 healthy workers (3556 men and 800 women) aged 19-69 years. The physical activity of each participant was classified according to the International Physical Activity Questionnaire (IPAQ). We defined four components of MetS diagnostic components in this study as follows: 1) high blood pressure (BP) systolic BP [SBP] ≥ 130 mmHg, or diastolic BP [DBP] ≥ 85 mmHg, or on medication; 2) dyslipidemia (high-density lipoprotein-cholesterol concentration <40 mg/dL, or triglycerides concentration ≥150 mg/dL, or on medication; 3) impaired glucose tolerance (fasting blood sugar concentration ≥ 110 mg/dL, or if less than 8 hours after meals ≥ 140 mg/dL), or on medication; and 4) overweight (body mass index [BMI] ≥ 25 kg/m(2)), or obesity (BMI ≥ 30 kg/m(2)). There were 680 participants in the group, with sleep duration <6 hours (15.6%).

RESULTS

Those who had 0-4 MetS diagnostic components, including overweight, accounted for 2159, 1222, 674, 255, and 46 participants, respectively, in the Poisson distribution. Poisson regression analysis revealed that independent factors that contributed to the number of MetS diagnostic components were being male (regression coefficient b = 0.752, P < 0.001), age (b = 0.026, P < 0.001), IPAQ classification (b = -0.238, P = 0.034), and alcohol intake (mL/day) (b = 0.018, P < 0.001). Short sleep duration (<6 hours) was also related to the number of MetS (b = 0.162, P < 0.001). The results of analyses with obesity component showed a similar association.

CONCLUSION

Short sleep duration was positively associated with the number of MetS diagnostic components independent of other lifestyle habits.

Population attributable fraction of smoking and metabolic syndrome on cardiovascular disease mortality in Japan: a 15-year follow up of NIPPON DATA90

Background

Smoking and metabolic syndrome are known to be related to cardiovascular diseases (CVD) risk. In Asian countries, prevalence of obesity has increased and smoking rate in men is still high. We investigated the attribution of the combination of smoking and metabolic syndrome (or obesity) to excess CVD deaths in Japan.

Methods

A cohort of nationwide representative Japanese samples, a total of 6650 men and women aged 30-70 at baseline without history of CVD was followed for 15 years. Multivariate-adjusted hazard ratio for CVD death according to the combination of smoking status and metabolic syndrome (or obesity) was calculated using Cox proportional hazard model. Population attributable fraction (PAF) of CVD deaths was calculated using the hazard ratios.

Results

During the follow-up period, 87 men and 61 women died due to CVD. The PAF component of CVD deaths in non-obese smokers was 36.8% in men and 11.3% in women, which were higher than those in obese smokers (9.1% in men and 5.2% in women). The PAF component of CVD deaths in smokers without metabolic syndrome was 40.9% in men and 11.9% in women, which were also higher than those in smokers with metabolic syndrome (7.1% in men and 3.9% in women).

Conclusion

Our results indicated that a large proportion of excess CVD deaths was observed in smokers without metabolic syndrome or obesity, especially in men. These findings suggest that intervention targeting on smokers, irrespective of the presence of metabolic syndrome, is still important for the prevention of CVD in Asian countries.

Gender difference of association between LDL cholesterol concentrations and mortality from coronary heart disease amongst Japanese: the Ibaraki Prefectural Health Study

OBJECTIVE

The aim of this study was to examine whether LDL cholesterol raises the risk of coronary heart disease in a dose-response fashion in a population with low LDL-cholesterol levels.

DESIGN

Population-based prospective cohort study in Japan.

SUBJECTS AND MAIN OUTCOME MEASURES

A total of 30,802 men and 60,417 women, aged 40 to 79 years with no history of stroke or coronary heart disease, completed a baseline risk factor survey in 1993. Systematic mortality surveillance was performed through 2003 and 539 coronary heart disease deaths were identified.

RESULTS

The mean values for LDL-cholesterol were 110.5 mg dL(-1) (2.86 mmol L(-1)) for men and 123.9 mg dL(-1) (3.20 mmol L(-1)) for women. Men with LDL-cholesterol > or =140 mg dL(-1) (> or =3.62 mmol L(-1)) had two-fold higher age-adjusted risk of mortality from coronary heart disease than did those with LDL-cholesterol <80 mg dL(-1) (<2.06 mmol L(-1)), whereas no such association for women was found. The multivariable hazard ratio for the highest versus lowest categories of LDL-cholesterol was 2.06 (95 percent confidence interval: 1.34 to 3.17) for men and 1.16 (0.64 to 2.12) for women.

CONCLUSION

Higher concentrations of LDL-cholesterol were associated with an increased risk of mortality from coronary heart disease for men, but not for women, in a low cholesterol population.

Psychological distress and cardiovascular disease: the Circulatory Risk in Communities Study (CIRCS)

Although a number of epidemiological studies have reported that psychological factors are associated with increased risk of cardiovascular morbidity and mortality, the relevant epidemiological data are mostly limited to Western populations. The present study sought to examine associations of depressive symptoms, anger expression, and tension with the incidence of cardiovascular disease in the Circulatory Risk in Communities Study (CIRCS). Depressive symptoms were measured in 901 men and women by using the Zung Self-Rating Depression Scale (SDS); anger expression and tension were measured in 6292 men and women by using the Anger Expression Scale and Framingham Tension Scale. As compared with the participants with SDS scores in the lowest tertile, those with scores in the highest tertile had twice the age- and sex-adjusted hazard ratio of total stroke. However, this excess risk was present only for ischemic stroke. Participants in the highest tertile also had a 7-fold adjusted hazard ratio of coronary heart disease, as compared with those in the lowest tertile. These associations were virtually unchanged after further adjustment for covariates. Men with “anger-in” scores in the highest tertile had a 1.5-fold age-adjusted relative risk of hypertension as compared with those in the lowest tertile; anger-in score was not associated with hypertension in women. In men and women, there were no associations between hypertension and either “anger-out” or tension scores. These findings generally support the hypothesis that—as is the case in Western populations—anger suppression and depression increase the risk of cardiovascular disease among Japanese.

Relationship among physical activity, smoking, drinking and clustering of the metabolic syndrome diagnostic components

AIM

To examine the relation between lifestyle and the number of metabolic syndrome (MetS) diagnostic components in a general population, and to find a means of preventing the development of MetS components.

METHODS

We examined baseline data from 3,365 participants (2,714 men and 651 women) aged 19 to 69 years who underwent a physical examination, lifestyle survey, and blood chemical examination. The physical activity of each participant was classified according to the International Physical Activity Questionnaire (IPAQ). We defined four components for MetS in this study as follows: 1) high BP: systolic BP > or = 130 mmHg or diastolic BP > or = 85 mmHg, or the use of antihypertensive drugs; 2) dyslipidemia: high-density lipoprotein-cholesterol concentration < 40 mg/dL, triglycerides concentration > or = 150 mg/dL, or on medication for dyslipidemia; 3) Impaired glucose tolerance: fasting blood sugar level > or = 110 mg/d, or if less than 8 hours after meals > or = 140 mg/dL), or on medication for diabetes mellitus; 4) obesity: body mass index > or = 25 kg/m(2).

RESULTS

Those who had 0 to 4 MetS diagnostic components accounted for 1,726, 949, 484, 190, and 16 participants, respectively, in the Poisson distribution. Poisson regression analysis revealed that independent factors contributing to the number of MetS diagnostic components were being male (regression coefficient b=0.600, p < 0.01), age (b=0.027, p < 0.01), IPAQ class (b=-0.272, p= 0.03), and alcohol consumption (b=0.020, p=0.01). The contribution of current smoking was not statistically significant (b=-0.067, p=0.76).

CONCLUSION

Moderate physical activity was inversely associated with the number of MetS diagnostic components, whereas smoking was not associated.

Fatty acids intakes and serum lipid profiles: NIPPON DATA90 and the national nutrition monitoring

Background

The National Nutritional Survey in Japan (NNSJ) was initiated in 1946. Using the majority of the participants for NNSJ, the National Survey on Circulatory Disorders (NSCD) has been conducted every 10 year since 1960. We compared fatty acids intakes obtained from NNSJ and serum lipid profiles from NSCD conducted in 1990.

Methods

A total of 8344 community residents (4856 women and 3488 men, age ≥ 30) from 300 randomly selected districts participated in the both surveys in 1990. At baseline, history, physical, and blood biochemical measurement and a nutritional survey were performed. We estimated nutrient intakes of each household member by dividing household intake data proportionally using average intakes by sex and age groups calculated for NNSJ95.

Results

Total fat, saturated fatty acids (SFA), poly-unsaturated fatty acids (PUFA), dietary cholesterol, and Keys dietary lipid factor (KEYS) were inversely associated with age in both men and women (all Ps < 0.001). In women, age and body mass index (BMI) adjusted serum total cholesterol (TC), high-density lipoprotein cholesterol (HDLc), and low-density lipoprotein cholesterol (LDLc) were positively associated with SFA, total fat intakes (%kcal), and with KEYS (P < 0.001). In men, age-BMI adjusted HDLc was not associated with SFA, total fat intakes, and with KEYS factors unlike in women. Other associations were similar to those in women.

Conclusions

The total fatty acids, SFA intakes, and KEYS lipid factor obtained from NNSJ were significantly associated with serum total and LDL cholesterol from the National Survey on Circulatory Disorders conducted in 1990.

Age-stratified analysis of the impact of hypertension on National Health Insurance Medical Expenditures in Ibaraki, Japan

Background

This retrospective cohort study examined the sex- and age-specific impact of hypertension on medical expenditures.

Methods

In 2006, we analyzed the medical expenditure records of 42 426 Japanese National Health Insurance beneficiaries (16 169 men, 26 257 women) who lived in Ibaraki, Japan, were aged 40 to 69 years, and underwent health checkups in 2002. Blood pressure was classified into 4 categories according to the criteria outlined in the seventh report of the Joint National Committee.

Results

The difference in median total expenditure between the hypertension categories and the normotension category was 119 585 yen (140 360 yen vs 20 775 yen) for men aged 40 to 54 years, 126 160 yen (204 070 yen vs 77 910 yen) for men aged 55 to 69 years, 125 495 yen (158 025 yen vs 32 530 yen) for women aged 40 to 54 years, and 122 370 yen (208 700 yen vs 86 330 yen) for women aged 55 to 69 years. The median total and outpatient medical expenditures markedly differed between patients with stage 1 hypertension and stage 2 hypertension (which included people on antihypertensive medication) in both sexes and all age subgroups. The median total and outpatient medical expenditures were higher among women than among men in all blood pressure categories.

Conclusions

The impact of hypertension on medical expenditures was similar in all age groups. Therefore, from the perspective of medical economics, prevention of the onset of hypertension seems equally important for all age subgroups.

Nocturnal intermittent hypoxia and metabolic syndrome; the effect of being overweight: the CIRCS study

AIM

We investigated whether nocturnal intermittent hypoxia, a surrogate marker for obstructive sleep apnea, is associated with metabolic syndrome and its components among Japanese.

METHODS

We examined 1,710 male and 2,896 female community-dwelling Japanese aged 40 to 69, who participated in annual cardiovascular examinations and investigations of sleep. Nocturnal intermittent hypoxia was estimated based on a 3% oxygen desaturation index measured with pulse-oximetry during sleep. No, mild and moderate-to-severe nocturnal intermittent hypoxia were defined by <5, 5 to <15 and >or=15 events/hour, respectively. Metabolic syndrome was defined by modified criteria of the Adult Treatment Panel III guidelines.

RESULTS

Compared with no nocturnal intermittent hypoxia, the multivariable odds ratio of metabolic syndrome was 1.9 (95% confidence interval: 1.6-2.4) for mild and 3.2 (2.2-4.7) for moderate-to-severe nocturnal intermittent hypoxia among men; 2.6 (2.1-3.4) and 5.8 (3.4-9.8) among women, respectively. When stratified by overweight status (body mass index >or=25 kg/m(2)), the multivariable odds ratio of two or more metabolic risk factors (other than overweight) associated with moderate-to-severe nocturnal intermittent hypoxia was 1.9 (1.2-3.1) among non-overweight subjects and 1.4 (0.9-2.1) among overweight subjects (p for interaction=0.002).

CONCLUSIONS

Nocturnal intermittent hypoxia was associated with the accumulation of metabolic risk factors, especially among non-overweight individuals.

Changes in Weight, cardiovascular risk factors and estimated risk of coronary heart disease following smoking cessation in Japanese male workers: HIPOP-OHP study

AIM

It is well established that people gain weight after smoking cessation; however, changes in cardiovascular risk factors and the estimated risk of coronary heart disease following smoking cessation have yet to be fully clarified.

METHODS

The participants were 1,995 Japanese male workers at 11 workplaces who participated continuously in the High-risk and Population Strategy for Occupational Health Promotion (HIPOPOHP) study. Participants with a smoking habit had cardiovascular risk factors measured at baseline and over a 4-yr period. Their estimated incidence risk of coronary heart disease was calculated by a formula based on a previous cohort study.

RESULTS

Successful abstainers who had stopped smoking for at least 6 months at the end of the follow-up period had weight gains of approximately 2 kg. These subjects had significant worsening of the following factors compared to continuing smokers: systolic and diastolic blood pressure, total cholesterol, triglyceride and fasting blood sugar levels. In contrast, HDL-cholesterol levels improved significantly. When the overall instantaneous incidence risk of coronary heart disease prior to smoking cessation was assumed to be 1.00, the estimated risk was 0.76 (95%CI: 0.68-0.85) in successful abstainers due mainly to smoking cessation, despite weight gain.

CONCLUSION

Although smoking cessation leads to weight gain, the estimated risk of coronary heart disease was decreased markedly by smoking cessation.

Association between non-high-density lipoprotein cholesterol concentrations and mortality from coronary heart disease among Japanese men and women: the Ibaraki Prefectural Health Study

AIM

The aim of this study was to examine whether non-high-density lipoprotein cholesterol (non-HDL-cholesterol) raises the risk of coronary heart disease in a dose-response fashion in a non-obese population with low total cholesterol levels and high HDL-cholesterol levels, such as Japanese.

METHODS

A total of 30,802 men and 60,417 women, aged 40 to 79 years with no history of stroke or coronary heart disease, completed a baseline risk factor survey in 1993 under the auspices of the Ibaraki Prefectural Health Study. Systematic mortality surveillance through 2003 identified 539 coronary heart disease deaths.

RESULTS

The mean values for non-HDL-cholesterol were 140 mg/dL for men and 151 mg/dL for women. The corresponding mean values were 193 mg/dL and 208 mg/dL total cholesterol and 52 mg/dL and 57 mg/dL HDL-cholesterol, respectively. Men with non-HDL-cholesterol > or = 180 mg/dL had a two-fold higher age-adjusted risk of mortality from coronary heart disease than did those with non-HDL-cholesterol <100 mg/dL, whereas no such association was found for women. The multivariable hazard ratio for > or = 180 mg/dL versus <100 mg/dL of non-HDL-cholesterol was 2.22 (95% confidence interval: 1.37 to 3.62) for men and 0.71 (0.37 to 1.34) for women.

CONCLUSION

Higher concentrations of non-HDL-cholesterol were associated with an increased risk of mortality from coronary heart disease for men, but not for women.

Relationship between obesity and incident diabetes in middle-aged and older Japanese adults: the Ibaraki Prefectural Health Study

OBJECTIVE

To investigate the age-specific relationship between body mass index (BMI) and risk of diabetes in a Japanese general population.

PARTICIPANTS AND METHODS

A cohort of Japanese men (N=19,926) and women (N=41,489) (aged 40-79 years) who under went community-based health checkups in 1993 and were free of diabetes was followed up by annual examinations with measurement of blood glucose concentrations until the end of 2006. Incident diabetes mellitus was defined as a blood glucose concentration of 126 mg/dL or greater under fasting conditions, 200 mg/dL or greater under nonfasting conditions, or diabetic medication use at baseline. Hazard ratios (HRs) for diabetes according to BMI were estimated using a Cox proportional hazard model. The model was adjusted for possible confounding variables.

RESULTS

A total of 4429 participants (7.2%) developed diabetes (2065 men and 2364 women) during a mean follow-up of 5.5 years. Compared with those with a BMI of less than 25.0, the multivariate HRs for diabetes among participants with a BMI of 30.0 or greater were 1.40 (95% confidence interval [CI], 0.89-2.20) for men aged 40 to 59 years and 1.26 (95% CI, 0.81-1.96) for men aged 60 to 79 years (P=.002 for interaction). The HRs were 2.50 (95% CI, 2.01-3.11) for women aged 40 to 59 years and 1.80 (95% CI, 1.41-2.30) for women aged 60 to 79 years (P=.04 for interaction).

CONCLUSION

The effect of obesity on the risk of diabetes is greater for middle-aged than for older adults.

Alcohol intake and 19-year mortality in diabetic men: NIPPON DATA80

Although moderate alcohol intake in diabetic Caucasians is associated with a reduction in coronary heart disease mortality, no study in Japanese with diabetes has examined the association between alcohol intake and mortality outcomes. We analyzed the relationship between alcohol intake and all-cause and cause-specific mortality using the database from NIPPON DATA80. At the baseline in 1980, data on history, lifestyle, and physical examinations were collected on study participants aged 30 years and older from randomly selected areas in Japan. After excluding participants with comorbidities, we followed 4,018 male participants (3,614 nondiabetics, 195 with impaired glucose tolerance and 209 diabetic) for 19 years. During the 19 years of follow-up, there were 990 deaths; 328 were from cardiovascular disease and 157 from all-heart diseases. With the never-drinking category serving as a reference, the Cox multivariate-adjusted hazard ratios for non-daily and daily drinkers for cardiovascular mortality were 0.43 (95% confidence intervals: 0.19-0.95) and 0.45 (0.25-0.80), respectively, and 0.33 (0.12-0.91) and 0.31 (0.15-0.67) for all-heart disease mortality in the combined impaired glucose tolerance and diabetic Japanese men. Alcohol drinking in men with glucose intolerance was associated with a significant reduction in cardiovascular and all-heart disease mortality as seen in the general population in Japan.

Measurement performance of reagent manufacturers by Centers for Disease Control and Prevention/Cholesterol Reference Method Laboratory Network lipid standardization specified for metabolic syndrome-focused health checkups program in Japan

AIM

This study was designed to clarify the current measurement performance of 7 reagent manufacturers for high-density lipoprotein cholesterol (HDLC), low-density lipoprotein cholesterol (LDLC) and triglycerides (TG) specified for the metabolic syndrome (MetS)-focused health checkups program in Japan.

METHODS

Twenty HDLC, 21 LDLC and 9 TG analytical reagent/instrument/calibrator systems (system), and combinations of reagent lots, instrument models and calibrator lots, underwent Centers for Disease Control and Prevention (CDC)/Cholesterol Reference Method Laboratory Network (CRMLN) lipid standardization. Eighty and 100% systems were requested to achieve an accuracy of within +/-1% and +/-2% of the reference value, so that a clinical laboratory can meet the CDC criteria.

RESULTS

The CDC performance criteria of HDLC, LDLC and TG require an accuracy of within +/-5%, +/-4% and +/-5%, respectively. For HDLC, all 20 systems met the criteria. Fourteen (70.0%) and 18 (90.0%) systems were within +/-1% and +/-2%, respectively. For LDLC, 14 (66.7%) of 21 systems met the criteria, but 7 (33.3%) failed. Five (23.8%) and 17 (81.0%) systems were within +/-1% and +/-2%, respectively. For TG, 8 of 9 systems met the criteria. Two (22.2%) and 4 (44.4%) systems were within +/-1% and +/-2%, respectively. The minimum and maximum differences of a specified sample among manufacturers were 1.6 and 11.0 mg/dL for HDLC, 7.8 and 33.0 mg/dL for LDLC, and 2.8 and 27.4 mg/dL for TG, respectively.

CONCLUSION

Homogeneous HDLC methods are acceptable for MetS, but further accuracy improvement of homogeneous LDLC and TG methods will be needed because of their poor performance.

Relationship of urinary cGMP excretion with aging and menopausal status in a general population

AIM

Aging and postmenopausal women are associated with increased risks of cardiovascular disease; however, epidemiological evidence concerning the relationship of aging and the menopause with vascular biological activity is limited.

METHODS

We investigated the relationship of aging and the menopause with urinary excretion of cyclic guanosine 3',5' monophosphate (cGMP) in 1,541 Japanese men and women aged 40 to 79 years. The 24-hour urinary excretion of cGMP was measured with a (125)I-labeled cGMP radioimmunoassay and was adjusted for urinary creatinine excretion (nmol/mmol creatinine).

RESULTS

Aging was positively associated with urinary excretion of cGMP for both sexes. Postmenopausal women excreted significantly less urinary cGMP than premenopausal women after adjustment for age and other cardiovascular risk factors: 48.3+/-0.04 nmol/mmol vs. 61.5+/-0.07 nmol/mmol, p=0.006.

CONCLUSIONS

Our data suggest that cGMP-related vasodilatation is impaired in postmenopausal women.

Impact of metabolic factors on subsequent cancer risk: results from a large-scale population-based cohort study in Japan

The impact of metabolic factors, which are major risk factors for cardiovascular disease, on total cancer risk has not been clarified. We prospectively examined whether metabolic factors and their aggregates predict the subsequent occurrence of total and major sites of cancer in the Japan Public Health Center-based Prospective Study. A total of 27 724 participants (9548 men and 18 176 women) aged 40-69 years participating in a questionnaire and health checkup survey in 1993-1995 were followed for total cancer incidence through 2004. Hazard ratios (HR) and 95% confidence intervals (CI) were calculated for metabolic factors and for two criteria of their aggregates (three or more than three factors and two or more than two additional factors in addition to being overweight) with a Cox proportional hazards model to control for potential confounding factors. In both sexes, the presence of metabolic factors in the aggregate did not predict subsequent occurrence of cancer as a whole. By site, a significant increase in risk was observed for male liver cancer [HR = 1.73, CI = 1.03-2.91 (three or more than three factors); HR = 1.99, CI = 1.11-3.58 (two or more than two additional factors in addition to being overweight)], and female pancreatic cancer [HR = 1.99, CI = 1.00-3.96 (two or more than two additional factors in addition to being overweight)]. For other sites, positive associations were observed only for specific metabolic factors, that is, high triglycerides and male colon cancer (HR = 1.71, CI = 1.11-2.62), and obesity and female breast cancer (HR = 1.75, CI = 1.21-2.55). Metabolic factors in the aggregate may have little impact on total cancer risk in the Japanese population, although the association between specific components and specific cancers suggests an etiologic link between them.

Associations between metabolic syndrome and mortality from cardiovascular disease in Japanese general population, findings on overweight and non-overweight individuals. Ibaraki Prefectural Health Study

BACKGROUND

The impact of being overweight, as a component of the metabolic syndrome (MetS), for cardiovascular disease (CVD) mortality was investigated and compared with the predictive value of MetS by 2 different definitions.

METHODS AND RESULTS

A 12-year prospective study of 30,774 Japanese men and 60,383 women aged 40-79 years was conducted. The multivariate hazard ratio (HR; 95% confidence interval) of total CVD mortality for overweight subjects with >or=2 additional risk factors with reference to subjects with 0 of 4 MetS components was 1.83 (1.41-2.38) for men and 1.90 (1.45-2.49) for women, and for non-overweight subjects with >or=2 additional risk factors 1.75 (1.38-2.24) and 1.97 (1.52-2.55), respectively. The proportion of excess CVD deaths in the latter group was 1.5-fold higher than that in the former group. Multivariate HRs of coronary heart disease and total CVD mortality for MetS by the modified criteria of the American Heart Association/National Heart, Lung, and Blood Institute were 1.62 (1.31-2.00) and 1.23 (1.09-1.39), respectively, for men and 1.32 (1.05-1.65) and 1.12 (1.00-1.25), respectively, for women. The respective HRs for MetS by the International Diabetic Federation definition did not reach statistical significance, except for coronary heart disease in men.

CONCLUSIONS

Non-overweight individuals with metabolic risk factors, as well as overweight individuals with such factors, should be targeted to reduce the CVD burden in the general population.

C-reactive protein levels and risk of mortality from cardiovascular disease in Japanese: the JACC Study

OBJECTS

Limited evidence of association between C-reactive protein levels and cardiovascular disease has been produced for Japanese whose median protein levels are low by western standards.

METHODS

We conducted a nested case-control study as part of the Japan Collaborative Cohort Study for evaluation of cancer risk (JACC Study). A total of 39,242 subjects 40-79 years of age provided serum samples at baseline between 1988 and 1990. During the 13-year follow-up, there were 525 deaths from total strokes (ICD10: I60-I69), 209 coronary heart diseases (I20-I25) and 939 total cardiovascular diseases (I00-I99). The control subjects were matched for sex, age, area of residence and year of serum storage, and analyses were conducted after further adjustment for cardiovascular risk factors. Serum high-sensitivity C-reactive protein (hs-CRP) levels were measured with ultra-sensitive latex-enhanced immunoassay.

RESULTS

Median hs-CRP levels for controls were 0.40 mg/L for men and 0.41 mg/L for women. Hs-CRP levels were positively associated with risks of mortality from stroke, coronary heart disease, and total cardiovascular disease for men. The respective multivariable odds ratios (OR 95% CI) for the highest (>or=0.85 mg/L) vs. lowest (<0.19 mg/L) quartiles of hs-CRP for men were 1.60 (0.90-2.85), 3.68 (1.02-13.3), and 2.31 (1.49-3.59). For women, positive associations with hs-CRP levels were weaker, reaching statistical significance only for total cardiovascular disease: OR=1.69 (1.06-2.68). The positive association with total cardiovascular disease did not vary according to sex, age, smoking status, or body mass index.

CONCLUSIONS

Higher serum hs-CRP levels were associated with higher mortality from cardiovascular disease in Japanese.